Conventionally, when a plurality of cooling instruments (including air-conditioning) are installed in the same floor, it has been proposed to control the plurality of cooling instruments appropriately by a control apparatus which is installed in one place, instead of controlling these cooling instruments separately (for example, Patent Literature 1).
In this conventional control apparatus, in order to perform operation according to the heat load around each cooling instrument, a stop time is preset for each cooling instrument. The value of this stop time is adjusted when each cooling instrument is installed, and then the value is used without being changed. The control apparatus that controls each cooling instrument is provided with a periodic time setting timer which is common to all the cooling instruments being connected, and the timer can be adjusted variably by a user. Therefore, when the heat load increases due to a change in the season, for example, it is controlled such that a desired temperature is achieved by increasing the periodic time common to all the cooling instruments and thus increasing the operating time.